open q: what’s the best / most respectful way to offer product feedback

eg. there are a few products I used or heard more about at Basecamp/FEST and I’d like to offer my critiques but not in a bashing manner 

have thought one cool avenue could be @0xdesigner style concepts for parts of products I’d like to see reworked

building products /neynar, hacking /farhack, yapping /dylan | dylansteck.com

Sometimes I receive feedback that I didn't ask for and don't want, especially because the feedback is usually coming from someone who doesn't have enough context or backstory to provide anything meaningful, so it's just tiring for me.  

When I do want feedback, I go to specific people who's perspective I value for that circumstance, and those experiences are almost always incredibly meaningful.